Embodiments of the system relate generally to an electric power grid and more specifically to power quality in a distribution network.
The basic structure of an electric power system comprises various hardware elements such as generators, transformers, and real-time monitoring equipment, and software such as power flow analysis software, fault detection software, and restoration software for generation, transmission, and distribution of electricity.
With increased distributed generation, the integration of distributed generators into existing power systems presents technical challenges such as voltage regulation, stability, and power quality issues. Power quality is an essential customer-focused measure and is greatly affected by the operation of a distribution and transmission network.
In general, power system operators ensure the quality of the power supplied to the customers by maintaining the load bus voltages within their permissible limits. Any changes to the system configuration or in power demands can result in higher or lower voltages in the system. In some situations the variability of the voltage level can be improved by reallocating the reactive power generated in the system such as by adjusting transformer taps and by switching volt-ampere reactive (VAR) sources such as capacitor banks. Another option is to use a series transformer to adjust the feeder voltages. However, transformer taps have limitations on the number of switchings per year and is not a satisfactory solution for frequent voltage variations. Furthermore, capacitor banks and the series transformer tend to require separate installations and may not work adequately for a lower reactance to resistance (X/R) ratio. Further the series transformer requires breaking the feeder line for installation.
For these and other reasons, there is a need for an improved power quality control system.